If you are going to use creatine supplements to assist with your muscle gain, you should use caution, especially when taking them for an extended period of time. These supplements should not be used if you have kidney problems. Additional known complications include muscle cramps and compartment syndrome. Creatine supplements have even been linked with heart arrhythmia. Creatine should be especially avoided by the young. Try to ensure that you use the supplements safely if you decide you are going to integrate them into your workouts.